Rotatable packed bed technology is commonly employed to separate impurities from gas streams. Unfortunately, many of the known processes and systems require large amounts of energy, complex equipment, and often result in poor separation. It would be desirable to discover new methods and systems that used less energy, result in good separation, and could employ readily available equipment.
The present invention relates to new methods and systems for removing impurities in gas streams using rotating packed beds. Advantageously, the new methods and systems often use less energy, result in good separation, and/or could employ readily available equipment.
In one embodiment, the invention pertains to a method for removing an impurity from a feed gas stream. The method comprises contacting in a rotating packed bed absorber a liquid solution capable of absorbing an impurity and a feed gas comprising an impurity. The rotating packed bed absorber comprises a packed bed with one or more rotatable packing rings having an interior region within the packed bed. The absorber is characterized by (1) at least one liquid inlet for infusing liquid into the interior region of the packing bed, (2) at least one gas inlet for infusing a feed gas into the interior region of the packing bed via the chamber; (3) at least one gas outlet for removing gas from the interior region of the packing bed; and (4) at least one liquid outlet for removing liquid from the interior region of the packing bed. The contacting occurs under conditions such that the liquid solution absorbs impurity to produce an impurity-rich liquid solution. The impurity-rich liquid solution is removed and the pressure of the impurity-rich liquid solution is reduced. At least a portion of any energy produced is recovered.
In another embodiment the invention relates to a system for removing an impurity from a feed gas stream. The system comprises a rotating packed bed absorber with one or more rotatable packing rings. The absorber is configured for contacting a feed gas stream comprising one or more impurities with a liquid to produce (1) an impurity-rich liquid solution comprising one or more absorbed impurities and (2) purified gas. A pressure reducing device is in fluid communication with the rotating packed bed absorber for receiving and reducing the pressure of the impurity-rich liquid solution and recovering energy therefrom. At least some of the energy recovered in the pressure reducing device may be employed to rotate the one or more rotatable packing rings of the rotating packed bed absorber.
In yet another embodiment the invention pertains to a system for removing an impurity from a feed gas stream. The system comprises a rotating packed bed absorber with one or more rotatable packing rings. The absorber is configured for contacting a feed gas stream comprising one or more impurities with a liquid to produce (1) an impurity-rich liquid solution comprising one or more absorbed impurities and (2) purified gas. A pressure reducing device is in fluid communication with the rotating packed bed absorber for receiving and reducing the pressure of the impurity-rich liquid solution and recovering energy therefrom. A regenerator for regenerating the impurity-rich liquid solution is operably linked to the pressure reducing device for regenerating the impurity-rich liquid solution for reuse in the rotating packed bed absorber. The regenerator and pressure reducing device are configured such that at least some of the energy generated in the pressure reducing device may be employed in regeneration.